Background Calcitonin gene-related peptide (CGRP) is the predominant neurotransmitter in capsaicin-sensitive sensory nerves. Participation of CGRP in hypertension is one of the most extensively studied topics in the field. There is growing evidence to the effect that CGRP is associated with essential hypertension (EH). The aims of this study were to pinpoint whether single nucleotide polymorphisms (SNPs) in the genes coding for CALCA were associated with EH susceptibility in a Hunan Han population.Methods Atotal of 293 subjects with EH and 208 controls were enrolled in the study. Genomic DNA was extracted from peripheral blood leucocytes by a phenol-chloroform method. The CALCA T-692C was genotyped using a restriction fragment length polymorphism method.Results A statistically significant difference in CALCA T-692C genotypic distribution was observed between cases and controls (P=0.001). Moreover, the frequencies of the C allele were 14.85% in the EH group and 7.45% in the control group, prevalence of C alleles in EH subjects and controls was significantly incomparable (P